Or if you are like me and don't intend to tweak the settings on the phone with any hacks or scripts, just buy a prepaid SIMCard from either the US or the UK that has ROAMING support. I got it from Ebay for RM10 (T-Mobile)... that's including shipping as well and it expires in a years time

Then put in the new SIM Card, let it connect to our local network via roaming, turn OFF DATA roaming (you want to use the WIFI connection in your house/office/area and not the credit from your foreign SIM Card), turn ON Wifi, head to Android Market.. and there you go, you can access all paid apps (I use Google Checkout to purchase my apps). You can also buy paid apps. After buying and downloading all you want, turn the phone off. Put in your local SIM card and you will notice that you can still access or UPDATE / REMOVE the apps that you have bought or downloaded using the US / UK Sim Card If you wish to download further paid apps or apps that aren't released in this part of the world, then you have to put in the foreign SIM Card again.

Hope that helps.

p.s It's better to get a US Sim Card that roams because some apps are restricted in the UK as well.